Does ride height matter?

[dly]

I have a 07 GT/CS that I autocross for fun with my local SCCA club. Last week end they had a outside photographer taking pictures and I asked if he could sent me a picture he took of my car. I'm running yellow Koni's, adjustable sway bar (at the tightest setting) adjustable sway bar links and steeda comp springs. The car rides high. A fellow club member has a Boss 302 and its a lot closer to the ground. I know my car will never be a Boss 302 but would Eibach pro springs lower my car and would I lose anything thing in doing it.
This is just my 3rd year in autocross and I'm still learning a lot from the forum members here.
I also have MM camber plates and just started running 295/30/18 Hoosier A6 tires this year. The car feels tight but I'm still a couple of seconds behind the leaders in my class. Seat time will help a lot but I do have some $$ to play with.



dly

 

[Whiskey11]

I have a 07 GT/CS that I autocross for fun with my local SCCA club. Last week end they had a outside photographer taking pictures and I asked if he could sent me a picture he took of my car. I'm running yellow Koni's, adjustable sway bar (at the tightest setting) adjustable sway bar links and steeda comp springs. The car rides high. A fellow club member has a Boss 302 and its a lot closer to the ground. I know my car will never be a Boss 302 but would Eibach pro springs lower my car and would I lose anything thing in doing it.
This is just my 3rd year in autocross and I'm still learning a lot from the forum members here.
I also have MM camber plates and just started running 295/30/18 Hoosier A6 tires this year. The car feels tight but I'm still a couple of seconds behind the leaders in my class. Seat time will help a lot but I do have some $$ to play with.

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dly

Does ride height matter? It sure does. A number of things change when you lower your vehicle and some are good and some are bad. One of the big things that changes is the CG height which can be a huge benefit to handling if you take advantage of it.

The biggest negative is all of the suspension geometry changes. At the front of the car you lose roll center height and the suspension starts in a worse part of the camber curve of the front suspension. That means significantly more static negative camber and higher spring rates to control the tire contact patch better. At the rear of the car you have the changes in %Anti-squat and %Anti-lift which can create brake dive and wheel spin on corner exit. Of course there is the reduction in bump travel too. Never mind the issue of roll steer that gets dicked with too.

What I caution against is lowering the car too far without taking corrective measures and without doing it appropriately. Your average lowering spring lacks the sufficient spring rate to keep the car off the bump stops. The only lowering springs I can think of that might have sufficient rate for the drop are the H&R race springs and the MM road and track springs. Beyond that you are looking into coilover springs or some custom rate springs if you can find a company that will make them for you. The lower you go the stiffer you need to get as well to properly control the chassis and keep the car off the bump stops.